This invention relates to the application of any one of a variety of ANR techniques to audiometry testing and to corresponding embodiments of audiometry testing headphones. Specifically, the reduction or cancellation of ambient noise of any spectral content existing in and/or around the vicinity of an audiometric testing facility is the main object of the invention. Audiometry testing stimuli are compensated in appropriate ways, after the application of the ANR method, resulting in accurate testing results that conform to standard calibration procedures. This invention includes the field of electronic equipment used for audiometry testing as well as the field of electronic devices used for personal ANR implementations.
Audiometric testing requires very low ambient noise levels in order to determine a subject""s hearing threshold level. (Ambient noise may refer to the noise heard by the user under the audiometric test headphones or to the noise in the immediate area surrounding the test subject. The specific meaning will be clear in the context of the subsequent discussion.) In the past, two methods have been used to achieve low ambient noise environments where test subjects can be accurately tested. Artificially quiet environments have been created by installing various sizes of soundproof testing booths (chambers or rooms) in locations that are otherwise too noisy. An alternative to this expensive option has been to add more passive attenuation materials to existing headphones, thus enclosing the ear in a chamber called a circumaural headphone architecture (such as the Audiocup). This option is not preferred by some audiologists because of non-uniformity of testing results caused by improper fitting of such headphones to the wearer. Recently, insert earphones were introduced into the industry as an alternative to booths and circumaural headphones. Although they are capable of providing accurate test results in higher ambient noise fields than most other test headsets, their low frequency insertion loss is unacceptably low for many noise fields. In addition, significant variability in testing results due to fitting issues has left a need to seek out new innovations for audiometric testing in noisy environments.
The use of ANR techniques to reduce the acoustic noise perceived by a human listener has become quite popular in the last ten years. There are numerous patents related to the art and many of those innovations are related to various configurations of ANR headsets. Although there are substantial variations among the different types of ANR headsets that are i existence, none of the headsets have been designed to be integral components in hearing evaluation equipment or for the purpose of improving the quality of audiograms generated in situ. The instant innovations significantly advance the state-of-the-art for ANR headphones, providing a completely new design process and fabrication than previously defined by prior inventors.
Accordingly, it is an object of this invention to reduce ambient noise in any audiometry testing environment, clinical or otherwise, by use of active noise control technology for the purpose of improving the accuracy of measured hearing thresholds in noisy environments and,
It is another initial object of this invention to provide active cancellation of ambient noise in audiometry over a wide frequency range and,
Yet another object of this invention is to provide for audiometric testing in high ambient noise conditions using active noise cancellation techniques and,
It is another object of this invention to use feedback control with analog and/or digital hardware and/or software to implement the active noise control in an audiometer and,
It is still another object of this invention to use feedforward control employing digital software and some external analog hardware to implement the active noise control in an audiometer and,
It is a further object of this invention to use both feedback and feedforward control simultaneously to implement the active noise control in an audiometer thereby selectively canceling different types of noise and,
It is yet another object of this invention to meet existing audiometry testing standards while incorporating active noise control into either a new or existing hearing testing device and,
Still further, It is an object of this invention to use active noise control in a headphone or headset system that is also used to perform audiometry testing thereby performing the active noise control and hearing testing simultaneously and,
It is a still further object of this invention to use the same or different actuator or actuators for delivering both the audiometry test stimulus and the active noise control signal and,
Furthermore It is an object of this invention to deliver any audiometer test signal to the test subject while attenuating the ambient noise with active noise control, in such a manner that the test stimulus is either not affected by the control process or the test results can be interpreted so as to factor the controller into the results and,
It is an additional object of this invention to deliver any audiometer test stimulus to the test subject through the same actuator or different actuators, while reducing the ambient noise using active noise control such that the nature of the test stimulus is independent from the control action and,
It is yet another object of this invention to provide an external device which can be used with any existing audiometer and requires no modification in order to realize the benefits of active noise reduction to any existing audiometry hardware and,
It is a final object of this invention to integrate the active noise control technology into a specially built audiometer that is either an existing audiometer that has been modified for the purpose of including the active noise control technology or an audiometer that is manufactured to have already incorporated in it, the active noise control technology.